Fluid-heating device

ABSTRACT

A fluid-heating device comprising a casing, outer and inner chambers therein, a hollow metal core about which spaced turns of Teflon-coated wire is wound and which wire constitutes a heater for raising the temperature of fluid flowing into the inner chamber to a preset range of temperature, a thermistor for sensing temperature of fluid discharged at the top of and from the inner chamber and being adapted for connection to an electrical circuitry which opens and closes a fluid valve associated with an inlet port for the outer chamber. The changers are separated from each other and a filter is provided about the core for preventing foreign material, dirt and the like from passing from the outer to the inner chamber. The core is provided with fluted passageways for upward circulation of the filtered water in the inner chamber.

United States Patent {72] Inventor Othmar W. Pies 200 W. Galbraith Road,Cincinnati, Ohio 45215 [21] Appl. No. 766,789

[22] Filed Oct. 11, 1968 [45] Patented June 1, 1971 [54] FLUID-HEATINGDEVICE 7 Claims, 8 Drawing Figs.

[52] U.S. Cl 219/307, 165/119, 219/308, 219/331, 219/334, 219/381,222/146 [51] Int. Cl F24h 3/00 [50] Field 01 Search 219/296- [56]References Cited UNITED STATES PATENTS 564,657 7/1896 Stiebel 219/319X793,118 6/1905 Wright et al. 219/299X 894,323 7/1908 l-lolt 219/30710/1913 .Ioerin et a1. 219/296X 1,335,020 3/1920 Papini 219/333X2,103,434 12/1937 Pennebaker 2l9/381(UX) 2,635,174 4/1953 Kasten219/381(UX) 3,235,084 2/1966 King et al.... 219/381(UX) PrimaryExaminer-A. Bartis Attorney-Pearce 8L Schaeperklaus ABSTRACT: Afluid-heating device comprising a casing, outer and inner chamberstherein, a hollow metal core about which spaced turns of Teflon-coatedwire is wound and which wire constitutes a heater for raising thetemperature of fluid flowing into the inner chamber to a preset range oftemperature, a thermistor for sensing temperature of fluid discharged atthe top of and from the inner chamber and being adapted for connectionto an electrical circuitry which opens and closes a fluid valveassociated with an inlet port for the outer chamber. The changers areseparated from each other and a filter is provided about the core forpreventing foreign material, dirt and the like from passing from theouter to the inner chamber. The core is provided with fluted passagewaysfor up ward circulation of the filtered water in the inner chamber.

F74 TEE PATENTEI] JUN 1 l9?! SHEET 2 [IF 2 FLUID-HEATING DEVICEBACKGROUN D OF THE INVENTION I Field ofthe Invention The field of art towhich this invention is most likely to pertain is generally located inthe class of apparatus relating to fluidor water-heating devices.

2. Description of the Prior Art Heating apparatuses, the art to whichthis invention most likely pertains, are disclosed in the following US.Pats.: Nos. 793,118; I,335,020;3,l97,6l3;and 3,247,359.

SUMMARY This invention relates to a device for instantaneously heatingfluid, and particularly relates to a water-heating device through whichtap water may be fed, circulated therethrough, and from which hot wateris instantaneously discharged.

An object of this invention is to provide for a novel fluidheatingdevice.

Another object of this invention is to provide for a deviceinstantaneously heating water and which is readily adaptable for use inother environments, an example of which is in the making of hot liquidcoffee.

A further object of this invention is to provide for a device whicheliminates the provision for storing water prior to heating thereof.

Another object of this invention is to provide for an efficient andeconomical device for heating fluid, in particular, water.

A still further object of this invention is to provide for a wideadaptability in actual application, such as in coffee makers, of theinvention due to its relatively small size.

A further object of this invention is to provide for the substantialelimination of liming and other deposits because of the controlled andlimited amount of water circulating through the heating portions of thedevice.

Another object of this invention provides for negligible maintenance onthe device which has no moving parts therein.

A still further object of this invention provides for manifolding thesedevices together for increasing total volume of heated water.

Another object of this invention provides for absence of the process ofsteaming or vaporization of the fluid while in the device, therebyeliminating maintenance and inefficiency otherwise developed as a resultof collection of deposits of foreign matter and the like.

Briefly, this invention provides a fluid heater which includes incombination, a sealed casing having an outer chamber and an innerchamber. A metallic core separates the chambers and is provided withhelically wound serrations on the periphery thereof. A plurality offluted surfaces formed longitudinally in such periphery providepassageways for circulation of fluid. A heater element is mounted aboutsaid serrations. Spaces are provided between turns of said heaterelement for passage of fluid from the outer chamber into thepassageways. A filter is mounted about said metallic core and the heaterelement. Fluid enters through an inlet port in the outer chamber, andpasses from the passageways into the inner chamber to be dischargedthrough an outlet port of the inner chamber.

These and other objects and advantages of the invention will become moreapparent upon a full reading of the following description, appendedclaims thereto, and the drawing comprising two sheets.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevational sectional viewof a device embodying the invention.

FIG. 2 is a view taken on line 2-2 of FIG. 1.

FIG. 3 is a view taken on line 3-3 of FIG. 1.

FIG. 4 is a view taken on line 4-4 of FIG. 1.

FIG. 5 is a fragmentary exploded view of a portion of a device embodyingthe invention.

FIG. 6 is a fragmentary exploded view of another portion of a deviceembodying the invention.

FIG. 7 is a fragmentary exploded view of still another portion of adevice embodying the invention.

FIG. 8 is a schematic diagram of an electrical circuit suitable for usein operation ofa device embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing inwhich reference characters therein correspond to like numeralshereinafter in the following description, reference character 20generally represents a device embodying the invention. Device 20comprises a hollow casing 21 having a base 22 and a cone-shaped top 23suitably tightly secured to casing 21 and sealed thereto by means ofO-rings 24 and 25, respectively, as shown in FIG. 1. One form ofsecuring casing base 22 and top 23 to casing 21 is shown in FIG. 1,wherein a frame comprising a pair of elongated bolts 26, 27 extendingthrough a cross frame member 28 mounted over and seated upon top 23 isheld in stationary position to a flat support member 29 by means of nuts30 in threaded engagement to bolts 26, 27 and which are tightenedagainst flat support member 29. Member 29 includes a rim 31 for seatingupon a shoulder 32 provided in base 22. Such securement provides forready disassembly and assembly of device 20.

An inlet port 33 (FIGS. 1, 3) is securely mounted to casing 21,preferably transversely to and midway of the latters length, forintroduction of fluid into an outer chamber 34 of device 20, while anoutlet or discharge port or conduit 35 is provided for an inner chamber36 of device 20. Port or conduit 35 is disposed in and extends throughthe center of coneshaped top 23 for delivery of heated fluid from innerchamber 36 to a remote or other desired point of further dischargetherefrom. An O-ring 37 seals port or conduit 35 in top 23 to preventleakage of fluid thereat, while a washer element 38 may be mounted aboveO-ring 37 and below crossmember 28 to prevent damage thereto in theassembly of device 20.

An aluminum core 39 is disposed within, spaced from and longitudinallyof casing 21, its lower end being seated in an annular recess 40 in base22 and its upper end being supported within a ring 41 mounted about core39. The inner diameter of ring 41 along its upper rim, FIG. 1, is of asmaller dimension than the outer diameter of core 39 whereby ring 41does not slide down upon core 39 and the upper terminal extremity ofring 41 seats in a slot 42 formed about the underside of coneshaped top23, upon tight assembly of device 20.

Aluminum core comprises a cylindrical tube having a plurality ofparallel fluted surfaces 43 extending longitudinally of its peripheryand a corresponding hole 44 connecting each fluted surface 43 to theinterior bore 45 of core 39. Holes 44 are provided adjacent the lowerend of core 39, as shown in FIG. 1. A series of helically woundserrations 46 are provided around the periphery of core 39 on thesurfaces thereof separating fluted surfaces 43 from each other, as shownin FIGS. 1 and 5. Coiled about core 39 and in serrations 46 is aTeflon-coated eIectricalcurrent-conducting wire 47 whose ends 48, 49(FIG. 6) begin and return to their respective connections with a pair ofcontacts 50, 51, respectively, securely mounted in base 22 forconnection to a suitable source of electrical energy. An aperture 52 isprovided through core 39 adjacent the lower limit of use of serrations46 for egress of wire 47 from its connection with one of contacts 50, 51to the exterior of core 39 for winding upwardly therearound inserrations 46, and an aperture 53 (FIG. 1) is provided through core 39adjacent the upper limit of use of serrations 46 for ingress of wire 47to the interior bore 45 of core 39 for return and connection to theother of contacts 50, 51, as shown in FIGS. 1 and 6. It may be notedhere that the length of ring 41 extends downwardly of core 39 to hole53. The upper extremity of the winding of wire 47 at the limit of hole53, overlap ofa filter 66 and the clampdown feature of top 23 upon ring41 maintain proper position of ring 41 on core 39 during and afterassembly of device 20.

FIG. 6 illustrates in detail a preferred connection of the ends of wire47 with its contacts 50, 51. Each contact 50, 51 includes a brass T-headportion 54 fitted to a hole 55 bored in base 22. T-head 54 is securedtherein by means of a brass retainer sleeve 56 threadedly engaging base22. Each end of wire 47 extends through a hole provided in base 22 forattachment to its contact 50, 51, and an Allen screw 57 is threadedlaterally into T-head 54 whereby each end 48, 49 of wire 47 is securedto its respective brass contact 50, 51. An ring 58 and washer 60 aredisposed in a reduced portion of hole 55, as shown in FlG. 6, and aremounted about the Teflon coating 62 on wire 47, whereby the interior ofcasing 21 is sealed and electrical elements 47, 50, 51 are insulatedfrom fluid contained in device 20.

A porous twill tape 64 is tightly wrapped helically about wound wire 47and core 39. Filter 66, preferably of synthetic material, is mounted inturn over tape 64. Wound tape 64 cooperates with ring 41 and a secondring 65 seated in annular base recess 40 about serrated core 39 forseparating inner chamber 36 from outer chamber 34 in addition tofunctioning with filter 66 to prevent foreign particles, dirt and thelike from clogging a spacing 68 of one twenty-thousandth inch providedbetween each turn of coated wire 47 wound on serrations 46 for passageof fluid into passageways 70 formed by fluted surfaces 43. Filter 66 andtape 64 further function to minimize circulation of fluid on the outsideof coils 47, i.e., they equalize flow of fluid or water through eachspacing 68. The upper limit of second ring 65 abuts lower hole 52 (incore 39) through which wire 47 egresses for winding in serrations FIG. 7illustrates a temperature-compensating resistor element 75, known as athermistor in the art, and which is utilized for sensing the temperatureof fluid discharged at conduit 35. Thermistor 75 preferably comprises aglass probe 76 securely mounted in top 23 by means of silicon cement 77sealing it in a hole in top 23 through which it extends. A pair of leads78, 79 (FIGS. 7, 8) incorporate thermistor 75 to within an electricalcircuitry 80 (FIG. 8) utilizable for heating wire 47 and operativelyopening and closing a solenoid valve 82 through which fluid or waterflows to inlet port 33 of device 20, thereby maintaining a desiredtemperature for fluid or water discharging through conduit 35. FIG. 8illustrates schematically a circuit for maintaining fluid temperaturewithin a preset range of values. However, it should be understood thatother electrical circuits may be utilized also in effecting control offluid temperature, understanding that the inventive concept does notextend beyond device 20.

Current lines 78, 79, in which thermistor 75 is disposed, are in essenceone side of a sensing bridge 84 included in general circuit 80. Sensingbridge 84 is balanced as long as the tem' perature of the dischargingfluid sensed by thermistor 75 is, say, l90 F. Should bridge 84 becomeunbalanced, the voltage output therefrom is either increased or reduced.Should such temperature fall below 190 F., such voltage output of bridge84 becomes negative and its collector voltage drops to a value wherebyan electronic switch of a silicon control rectifier (SCR) unit 86connected to bridge 84 does not trigger or close. As a consequence, nocurrent flows along current line 88 to one side of solenoid valve 82 andvalve 82 thus is mechanically in closed position. Should temperaturerise above 190 F., the resistance of thermistor 75 falls to a very lowvalue, the bridge 84 again becoming unbalanced but with a positivevoltage output sufficient to feed an amplifier 90 connecting SCR unit 86with bridge 84.

Amplifier 90 comprises two stages: a differential amplifier withtransistors and a common emitter amplifier. A voltage signal ofsufficient value from sensing bridge 84 is sufficient to cut off suchtransistors, thereby raising the collector voltage of bridge 84 andchanging the value of capacitance in a capacitor C. When suchcapacitance reaches a high enough value, increased voltage in SCR unit86 triggers its switch thereby sup plying current through line 88 tosolenoid valve 82, opening the latter to provide for flow of fluidtherethrough to inlet port 33 of device 20. Should temperature of thefluid again fall below 190 F., output voltage of bridge 84 is reduced,the transistors of the differential amplifier of amplifier 90 becomesaturated, and the collector voltage of bridge 84 drops, therebyreducing the voltage in SCR unit 86 to a degree where its switch doesnot trigger current to solenoid valve 82, thus valve 82 closing.

It should now be apparent that when the temperature of the fluid beingdischarged at port 35 is above l90 F., the function of thermistor 75 incircuitry maintains solenoid valve 82 in an open condition.

A temperature-limiting circuit may be included in circuitry 80 forclosing valve 82 when the temperature of the fluid at port 35 exceeds apredetermined value such as, say, 210 F.

When an adjustable resistor or resistance 92 in such circuit is soadjusted that voltage output in an SCR unit 96 including an electronicswitch is reduced, no current flows through line 94 to coiled wire orheater element 47. Resistor 92 may be manually adjustable for increasingor reducing its resistance whereby voltage output from amplifier 90,which is indicative of the temperature of the fluid at port 35 sensed bythermistor 75, be of too great a value, say, of a value correlated to atemperature of 210 F., then resistor 92 reduces the voltage output ofSCR unit 96 thereby opening the electronic switch in SCR unit 96 in line94 leading to coiled wire 47, in the same manner as reduction of voltagein sensing bridge 84 opens the electronic switch in SCR unit 86.

A timer circuit including a timer 98, operating offa l lS-volt ACconventional source, may be included in a portion of circuitry 80 inwhich current is fed to coiled wire 47. Such time circuit is basicallyone in which capacitors are continually charging and dissipating, thusincreasing and reducing voltage therethrough. By setting timer 98 to adesired length of time, say, 1 to 3 minutes, current from a ll5-volt ACsource 100 is supplied for such time setting to coiled wire or heater 47through line 94. Timer 98 becomes operative upon the fluid temperatureat port 35 falling below, say, l F. However, no timing action of timer98 occurs when such temperature is above 190 F. Controls for carryingout the function of timer 98, as well as for designing thecharacteristics of the components of the other electrical elementsoutlined above are able to be developed by one skilled in the electroniccircuit design art, and it should be understood that the disclosure ofthe schematic illustrated in FIG. 8 does not constitute a part of theinvention claimed herein, but is included merely to show one environmentto which device 20 is readily adaptable.

OPERATION A main electric switch (not shown) in the ll5-volt AC sourceis closed, thereby energizing one side of solenoid valve 82 through aline 102, energizing timer 98 in the timer circuit and supplying currentto coiled wire or heater 47 through SCR unit 96 and line 94. When waterabout thermistor 75 attains a temperature of F., timer 98 isinactivated. The sensing by thermistor 75 of a temperature higher than190 F. transmits a signal to the other side of valve 82 through sensingbridge 84, amplifier 90 and SCR unit 86, thereby opening valve 82 andthus providing for flow of water into inlet port 33 of device 20. Waterpasses from outer chamber 34 into inner chamber 36 via metering thereofthrough filter 66 and twill or porous tape 64, into spacings 68 andpassageways 70, and through apertures 44 from bore 45 of core 39 topassageways 70, it being exposed to heated coiled wire or heater 47,causing the water to flow upwardly along passageways 70 to dischargeport 35.

Thus, temperature of the water is heated to the desired level and therange of the temperature of water being discharged at port 35 iscontrolled by the temperature-limiting circuit thus limiting the degreeof temperature of discharged water from device 20.

When fluid or water temperature exceeds, say, 210 F., line 94 becomesnonconductive by operation of the temperaturelimiting signal or circuit.Valve 82 nevertheless remains open, continuing to provide forintroduction of cooler water into device 20, thereby regainingtemperature conditions of the circulating water to within the presetrange provided by circuitry 80.

Should thermistor 75 sense an abnormally low temperature for thedischarging water, below l90 F., line 88 becomes nonconductive and valve82 closes until heated wire 47 raises the temperature of the upwardlycirculating water, say, to 190 F. again. Valve 82 then again opens.

A pressure regulator (not shown) is preferably series-connected to valve82 for controlling the pressure of fluid or water flowing therethroughto a preferred degree.

Calibration of circuitry 80 may be monitored by a visual signal (notshown) such as a l l-v. lamp shunted across valve 82, whereby its openor closed condition, which reflects the preset range of temperatures,may be observable and controlled.

An advantage not apparent in prior art devices providing for heating ofwateror the like is found in the purpose of holes 44 in core 39. Holes44 together with internal bore 45 provide for displacement of waterthroughout inner chamber 36 during operation of device 20, therebypreventing steaming or vaporizing of water in device 20 before dischargeof the heated fluid. Consequently, no liming or other deposits occurred.A clean and reliably efficient operation results, as practice of theinvention indicates.

Pursuant to the requirements of the patent statutes, the principle ofthis invention has been explained and exemplified in a manner so that itcan be readily practiced by those skilled in the art to which itpertains, or with which it is most nearly connected, suchexemplification including what is presently considered to represent thebest embodiment of the invention. However, it should be clearlyunderstood that the above description and illustrations are not intendedto unduly limit the scope of the appended claims, but that therefrom theinvention may be practiced otherwise than as specifically described andexemplified herein, by those skilled in the art, and having the benefitof this disclosure.

Therefore, what-l claim as patentably novel is:

1. A fluid-heating device comprising in combination,

a sealed casing having a top and base,

a metallic core disposed in said casing and having a bore communicatingwith the exterior of the core,

helical serrations on the external periphery of said core,

a plurality of fluted surfaces formed longitudinally in said externalperiphery thereby providing for passageways for circulation of fluid,

a helically wound heating element mounted about said serrations,

a spacing being provided between adjacent turns of said heating elementfor passage of fluid into said passageways,

means for energizing the heating element,

a filter coextensive in length with the heating element mounted aboutsaid metallic core and heating element,

there being an inner chamber inside the bore of the core and an outerchamber inside the casing surrounding the filter, an inlet port to theouter chamber,

there being fluid flow communication means between the passageways andthe interior of the core, and

an outlet port from the inner chamber,

whereby fluid flowing through said inlet port, through said outerchamber, filter, and each spacing and passageway may be instantaneouslyheated before discharge at said outlet port.

2. The device of claim 1 including a porous tape wrapped about saidheat-conducting element and disposed between such element and saidfilter, and a pair of rings respectively seated in said top and basemounted about said core and to which said tape is attached 3. The deviceof claim 1 in which the fluid flow communication between said assagewaysand bore is'forrned by at least one hole 15 provi ed in said corebetween said passageways and bore.

4. The device of claim 3 wherein the heating element is electricallyenergized and electrical contact means for said heating element ismounted in said casing.

5. An instantaneous heating device for a fluid comprising a sealedcasing defining an outer chamber about a metallic core having a boreforming an inner chamber communicating with the exterior of the core,

a plurality of fluted surfaces formed longitudinally in the externalperiphery of said core to define passageways extending along theexternal periphery;

helically disposed serrations formed on such periphery,

electrical heating means wound about said serrations and electricallyinsulated from the core and having spacing between adjacent turnsthereof and adapted for connection to an electrical source,

means including a filter positioned about said heating means,

an inlet port for said casing connected to said outer chamber, therebeing fluid flow communication means between the passageways and theinterior of the core, and

an outlet port for said casing connected to said inner chamber,

whereby water passing from said outer chamber into said inner chamber ismetered through said means including said filter into and through saidspacing for instantaneous heating thereof, and circulating toward andbeing discharged from said outlet port.

6. The device of claim 5 in which said means includes a porous tapewrapped about said heating means and disposed between said heating meansand said filter, and a pair of rings respectively seated in the top andbase of said sealed casing and to which said tape is attached.

7. The device of claim 5 in which at least one hole is provided in thewall of said core for providing said communication between its bore andsaid passageways.

1. A fluid-heating device comprising in combination, a sealed casinghaving a top and base, a metallic core disposed in said casing andhaving a bore communicating with the exterior of the core, helicalserrations on the external periphery of said core, a plurality of flutedsurfaces formed longitudinally in said external periphery therebyproviding for passageways for circulation of fluid, a helically woundheating element mounted about said serrations, a spacing being providedbetween adjacent turns of said heating element for passage of fluid intosaid passageways, means for energizing the heating element, a filtercoextensive in length with the heating element mounted about saidmetallic core and heating element, there being an inner chamber insidethe bore of the core and an outer chamber inside the casing surroundingthe filter, an inlet port to the outer chamber, there being fluid flowcommunication means between the passageways and the interior of thecore, and an outlet port from the inner chamber, whereby fluid flowingthrough said inlet port, through said outer chamber, filter, and eachspacing and passageway may be instantaneously heated before discharge atsaid outlet port.
 2. The device of claim 1 including a porous tapewrapped about said heat-conducting element and disposed between suchelement and said filter, and a pair of rings respectively seated in saidtop and base mounted about said core and to which said tape is attached3. The device of claim 1 in which the fluid flow communication betweensaid passageways and bore is formed by at least one hole is provided insaid core between said passageways and bore.
 4. The device of claim 3wherein the heating element is electrically energized and electricalcontact means for said heating element is mounted in said casing.
 5. Aninstantaneous heating device for a fluid comprising a sealed casingdefining an outer chamber about a metallic core having a bore forming aninner chamber communicating with the exterior of the core, a pluralityof fluted surfaces formed longitudinally in the external periphery ofsaid core to define passageways extending along the external periphery,helically disposed serrations formed on such periphery, electricalheating means wound about said serrations and electrically insulatedfrom the core and having spacing between adjacent turns thereof andadapted for connection to an electrical source, means including a filterpositioned about said heating means, an inlet port for said casingconnected to said outer chamber, there being fluid flow communicationmeans between the passageways and the interior of the core, and anoutlet port for said casing connected to said inner chamber, wherebywater passing from said outer chamber into said inner chamber is meteredthrough said means including said filter into and through said spacingfor instantaneous heating thereof, and circulating toward and beingdischarged from said outlet port.
 6. The device of claim 5 in which saidmeans includes a porous tape wrapped about said heating means anddisposed between said heating means and said filter, and a pair of ringsrespectively seated in the top and base of said sealed casing and towhich said tape is attached.
 7. The device of claim 5 in which at leastone hole is provided in the wall of said core for providing saidcommunication between its bore and said passageways.